This is a grant renewal for studies on formulations of high molecular weight (MW>100 Daltons) pharmaceutical agents, such as DNA. Specifically, we plan to apply our understanding and experience in protein stabilization and controlled release system to the stabilization and controlled release of plasmid DNA. The significance of controlled release DNA lies in the significance of gene therapy. Currently, there are almost 400 gene therapy protocols. In clinical trials worldwide spanning a range of disease states (e.g., cancer, monogenic diseases, infectious diseases). The safe and effective delivery of gene therapeutics remains elusive and is currently a bottleneck for gene delivery. The stabilization of DNA in viable long-term pharmaceutical preparations is one critical part toward the advance of gene therapy to the clinic. There is a clear lack of understanding of the physical and chemical degradation of plasmid DNA in pharmaceutical systems, particularly with respect to degradation within hydrophobic polymer matrices. It is necessary to understand the relationship among plasmid DNA degradation pathways that occur under these conditions to begin designing rational methods for their stabilization. Therefore, our Specific Aims are: 1) Identify the principal non-enzymatic degradation pathways of supercoiled, nicked and linear plasmid DNA as a function of dehydration method, DNA packing, DNA hydration, and DNA conformation, (2) Identify new DNA stabilizing excipients or excipient combinations, 3) identify the principal non- enzymatic degradation pathways of supercoiled, nicked and linear plasmid DNA degradation in fully hydrated polymer-based controlled release systems,, the DNA-containing systems will be placed under a wide range of pharmaceutically relevant conditions and the degradation patterns identified by established analytical tools. The long-term objectives of this research are to develop robust DNA stabilization methods to meet the pharmaceutical requirements for controlled release gene delivery systems.